diff --git a/class/saturnesignature.class.php b/class/saturnesignature.class.php
index 86f87fcf..cc1f4747 100644
--- a/class/saturnesignature.class.php
+++ b/class/saturnesignature.class.php
@@ -323,7 +323,7 @@ public function fetchAll(string $sortorder = '', string $sortfield = '', int $li
             foreach ($filter as $key => $value) {
                 if ($key == 't.rowid') {
                     $sqlwhere[] = $key . '=' . $value;
-                } elseif (in_array($this->fields[$key]['type'], ['date', 'datetime', 'timestamp'])) {
+                } elseif (isset($this->fields[$key]['type']) && in_array($this->fields[$key]['type'], ['date', 'datetime', 'timestamp'])) {
                     $sqlwhere[] = $key . ' = \'' . $this->db->idate($value) . '\'';
                 } elseif ($key == 'customsql') {
                     $sqlwhere[] = $value;